A typical programmable integrated circuit may use transistors to implement programmable switches, which are needed for both programmable logic and programmable routing structures within the integrated circuit. N-type metal-oxide-semiconductor (NMOS) pass gates may be used to implement the programmable switches in some cases, while in other cases, static complementary metal oxide semiconductor (CMOS) pass gates with both NMOS and P-type metal-oxide-semiconductor (PMOS) transistors may be used to implement the programmable switches. For either one of these cases, voltage reliability requirements may prevent too high a voltage from being applied across any two ports of the NMOS or PMOS transistors.
Instead of using NMOS or PMOS transistors for the programmable structures, alternative switch structures are continually being evaluated for use within a programmable integrated circuit. The alternative switch structures are generally non-volatile, which means that the switch structures do not lose programming state when the power supply is powered down. But in order to program these non-volatile alternative switch structures, a higher voltage is typically needed to facilitate the switch programming. The need for the switches to maintain their programmed operations during normal mode of operation (i.e., without getting accidentally reprogrammed) implies that the programming voltage must be at a higher voltage than the normal logic operating voltage of the integrated circuit. However, the problem of overdriving other circuit elements such as logic circuits may arise when providing the higher voltage to the switch structures. Such a problem may cause device reliability issues and subsequently lead to device failure.